Signature stitching machine having apparatus for preventing the stitching and diverting the delivery of defective groups of signatures



Nov. 9, 1954 E. w. BELLUCHE ETAL 2,593,595

v SIGNATURE STITCHING MACHINE HAVING APPARATUS FOR PREVENTING THESTITCHING AND DIVERTING THE DELIVERY OF DEFECTIVE GROUPS OF SIGNATURES 9Sheets-Sheet 1 Filed June 11, 1952 "5 Mom .F/mpr .W 51 /u:/7p EmmaEBAY/Y2? 0 ES wm ne RN M AIN PTG w RI A m GIF g8 DS AN %HAW cmm um LCnwW LATI ma Bmsmm E wwm F Tm um ENE REV UVI TEL ARE WPD I Nov. 9, 1954Filed June 11, 1952 9 Sheets-Sheet 2 Nov. 9, 1954 E. w. BELLUCHE ETALSIGNATURE STITCHING MACHINE HAVING APPARATUS F0 PREVENTING THE STITCHINGAND DIVERTING THE DELIVERY OF DEFECTIVE GROUPS OF SIGNATURES Filed June11, 1952 9 Sheets-Sheet 5 Nov. 9, 1954 E. w. BELLUCHE ETAL 2,693,595SIGNATURE STITCHING MACHINE HAVING APPARATUS FOR PREVENTING THESTITCHING AND DIVERTING THE DELIVERY OF DEFECTIVE GROUPS OF SIGNATURESFiled June 11, 1952 9 Sheets-Sheet 4 34.8.5, ;L 93 mm 1m I i'Ull I xoz alZZ mun "H 9, 1W mm ll mm mm H 54 mm HIHI mm; mam

Nov. 9, 1954 E. w. BELLUCHE ETAL 2,693,595 SIGNATURE STITCHING MACHINEHAVING APPARATUS FOR PREVENTING THE STITCHING AND DIVERTING' THEDELIVERY OF DEFECTIVE GROUPS OF SIGNATURES Filed June 11, 1952 9Sheet's-Sheet 5 me I g g 1 I55 a W $660M Nov. 9, 1954 E. w. BELLUCHEETAL ,693,595

SIGNATURE STITCHING MACHINE HAVING APPARATUS FOR PREVENTING THESTITCHING AND DIVERTING THE DELIVERY OF DEFECTIVE GROUPS OF SIGNATURES'Filed June 11, 1952 9 Sheets-Sheet 6 Ezwrgw ff .5051? 45 g Nov. 9, 1954E. BELLUCHE AL 2,693,595

SIGNATURE STIT NG-- MACHINE HAV APPARATU 0R PREVENTI THE STITCHING ANDDIVE NG T DELIVERY DEFECTIVE GROUPS OF S ATURES Filed June 11, 1952 9Sheets-Sheet 7 I IIII ,QZ

H||||||llllllllllllllm CHE NE B NG Nov. 9, 1954 E. w. ELLU ET AL2,693,595 STITCHI MACHI ING APPARATUS FOR NG THE STITCHING DIVERTING THEOF DEFECTIVE GROUPS OF SIGNATURES eats-Sheet 8 HAV AND mm EN REW- U VITEL A 2 w I l S I l l e n u J d e l 1 F Nov. 9, 1954 E. w. ELLUCHE ETAL2,693,595 TURE STITCHING MACHINE HAVING APPARATUS FOR NG THE STITCHINGOF DEFECTIVE GRO AND DIVERTING THE SIGNA PREVENTI DELIVERY Filed June11, 1952 UPS OF SIGNATURES 9 Sheets-Sheet 9 United States PatentSKGNATURE STETCHING MACHINE HAVING AP- PARATUS FOR PREVENTING THESTITCHING AND DIVERTEIJG THE DELIVERY OF DEFEC- TIVE GROUPS OFSIGNATURES Elmer W. iieilnche and George H. Bohn, Racine, Wis.,

assignors to The Christensen Machine Company, Racine, Wis a corporationof Wisconsin Application June 11, 1352, Serial No. 292,962 27 Claims.((31. 1-406) This invention relates generally to book stitching machinesof the type used, for instance, to stitch together the individual foldedsheets or signatures ofmagazines by driving wire staples through thefolded backs thereof; and has as its objective to improve the manner ofdetecting the reception by the machine of a defective group ofsignatures and in consequence thereto preventing the functioning of thestitching mechanism when that group of signatures arrives thereat anddiverting the defective group of signatures into a discard path when itreaches the delivery end of the machine.

Stitching machines of the type here concerned have a plurality ofloading stations upon which operators place the individual signatures,that is, the folded sheets, to be gathered into books by spaced pusherson a conveyor chain which travels successively past the several loadingstations. The gathered groups of signatures are deposited by theconveyor chain onto the receiving end of a saddle which forms part ofthe stitching machine and along which the groups of signatures areadvanced by a reciprocating feed mechanism including a plurality ofgripper fingers.

The machine operates cyclically and with each cycle the feed mechanismadvances the groups of signatures on the saddle a definite distance.Normally a group of signatures is advanced in one cycle from itsposition on the receiving end of the saddle upon which it is depositedby the conveyor chain to a position under the stitcher heads which drivethe wire staples through the groups of signatures, and on the nextsuccessive cycle the stitched book is advanced from its stitchingposition to delivery position where a delivery mechanism discharges thebook onto a table-like delivery conveyor.

It is, of course, important that only complete groups of signaturesshall be stitched and that any group of signatures which contains morethan the prescribed number of pages and any group of signatures whichcontains less than the prescribed number of pages shall not be stitchedand in addition shall not be delivered onto the delivery conveyor.

Many dilferent detector mechanisms have been proposed and employed inthe past for the purpose of assuring that only good books will bestitched and delivered. The early schemes, as mentioned in Patent No.1,716,773 issued June 11, 1929, employed calipering devices fordetecting deviation from the prescribed thickness of the groups ofsignatures, but these early calipering devices had many deficiencies andobjections which led to the development of the detector arrangementcovered by the aforesaid patent. However, none of the expedients usedheretofore has been reliably accurate, especially at high speeds andwhere inserts such as mailing cards are incorporated in the books beingstitched.

This invention returns to the use of a calipering device sensitive todeviations in thickness of the groups of signatures, but provides acalipering mechanism which is accurately reliable at all operatingspeeds.

One of the problems that must be contended with in calipering thethickness of the work arises from the fact that the groups of signaturesto be stitched vary in thickness along the length thereof. This is, ofcourse, obvious where card inserts are incorporated, but it may alsoresult from the nature and distribution of the printing on thesignatures. In any event this variation in thickness along the length ofthe groups of signatures makes it imperative, if accurate calipering isto be obtained, that the actual calipering of work be done for only ashort length thereof and always at the same place.

2,693,595 Patented Nov. 9, 1954 Thus, for instance, where a magazine orbook to be stitched measures fourteen (14) inches in length it may verywell be that in order to secure accurate calipering only the last inchor two of the advancing group of signatures should be calipered. But, ifa calipering mechanism or detector is set to feel for only such a shortlength of the advancing group of signatures it is difficult, if notentirely impossible, to have reliable accuracy, especially at highspeeds.

To meet this problem the present invention provides a novel caliperingapparatus wherein companion feeler members, and more specifically a pairof rolls, grip the advancing group of signatures well in advance of therelatively short portion thereof which is actually calipered to thusgive the mechanism an opportunity to settle so that when the actualcalipering takes place a reliable measurement is assured.

This objective is achieved through the provision of a pair of electricswitches connected in series in a control circuit, the completion ofwhich effects the required lock-out of the stitcher heads and preventsthe delivery mechanism from delivering the defective group of signaturesonto the delivery table. One of these electric switches is controlled bythe caliper rolls to be closed by change in the distance between themresulting from deviation from the prescribed thickness of the group ofsignatures at the portions thereof being calipered. In other words, oneof these switches is closed if the group of signatures is too thick ortoo thin at the point at which the calipering is done.

The other switch is controlled by a cyclically operating cam to beclosed for a short interval once each cycle of the machine and, ofcourse, the cam controlling this switch must be set to effect itsclosure at the time the portion of the group of signatures to becalipered is passing between the companion feeler rolls. Concurrentclosure of both switches completes the control circuit and throughappropriate mechanism closure of this circuit prevents operation of thestitcher head or heads when the defective group of signatures ispresented thereto and upon its arrival at the delivery station a routingdirector is actuated to reject the defective group of signatures andkeep it from being delivered onto the good book delivery table.

Obviously the location at which the actual calipering is to be done willvary with different books so that the instant when the cyclicallyoperated switch closes must be adjustable to take place at any time inthe cycle. Also, since the books for which a particular stitchingmachine is designed will vary in length between relatively Wide limitsit is essential that the so-called downtime of the calipering rolls,that is, the time for which the rolls are effective and grip the passinggroups of signatures, be capable of adjustment.

This invention recognizes these requirements and has as another of itsobjects to provide means for so adjusting both the timing of thepositively regularly closed switch and the down-time of the feelerrolls. Since the logical position of the caliper is near or ahead of thereceiving end of the saddle on the machine so as to act on the groups ofsignatures as they are being presented by the conveyor chain to thereceiving end of the stitching machine, it follows that the lock-out ofthe stitcher heads to prevent the stitching of a bad book or group ofsignatures must occur during a cycle subsequent to that during which thecalipering is done.

This invention, therefore, has as another of its objects to provide areliable control mechanism which is activated by closure of the controlcircuit during one cycle of the machine, to take effect on the mechanismpreventing the operation of the stitcher head during a subsequent cycleof the machine and to act upon the routing director of the deliverymechanism during an even later cycle of the machine.

In this connection it is a further object of this invention to provide acontrol mechanism by which the stitcher head is locked out and therouting director of the delivery mechanism is actuated during cycles ofthe machine subsequent to that during which the detection of a defectivegroup of signatures was made, and wherein 'optimum reliability andaccuracy are secured by virtue of the fact that the mechanism operatesmechanically and positively.

Another problem which increases the difliculty of reliably detecting thepresence of a defective group of signatures results from the need foraccommodating relatively short books as, for instance, .books no more.than five or six inches in length. The trailing end of a group ofsignatures just deposited upon the saddle of .the machine by theconveyor chain is, of course, always 'in the same position regardless ofthe length of the book being stitched, but the location of the .centerof .the book from which all positioning .is done varies considerably,and in very short books this means that two cycles of the machine mustbe devoted to advancing a book from its position on the receiving end ofvthe machine saddle to a centered position in the work zone under thestitcher heads, and again from the work zone to the delivery mechanism.This, of course, increases the time delay required; and to provide thisadditional time when it is needed, it is another object of the inventionto provide a control which may be quickly and easily set .to effecteither single or multiple cycle delay.

With the above and other objects in view, which will appear as thedescription proceeds, this invention resides in the novel construction,combination and arrangement of parts substantiallyas hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes 'in the precise embodiment of thehere'indisclosed invention may be made as come within the scope of theclaims.

The accompanying drawings illustrate one complete example of thephysical embodiment of the invention constructed according to the bestmode so far devised for the practical application of the principlesthereof, and in which:

Figure 1 is a perspective view of a signature stitching machineembodying this invention;

Figure '2 is a vertical sectional view through the machine taken on theplane of the line 2-2 in Figure 1, said view having parts thereof brokenaway for the sake of clarity;

Figure 3 is a top view of the calipering mechanism per se, taken on theplane of the line 3-3 in Figure 2, but on an enlarged scale;

Figure 4 is a sectional view through Figure 5 on the plane of the line44, illustrating particularly the manner .in which the movablecalipering roll is driven, parts of said view being broken away and insection to better illustrate constructional details;

Figure 5 is a long'itudinal sectional view taken through Figure 3 on theplane of the line 5-5;

Figure -6 is an exploded perspective view of the cam which controls thedown-time of the caliper roll;

Figure 7 is an uprightzsectional view through Figure v8 on the plane ofthe line 7-7 and illustrating the top or movable one of .the companionfeeler 'rolls and the switch actuating pendulum driven thereby;

Figure 7a is a fragmentarydetail .view illustrating the manner in which'the switch actuating pendulum :is drivingly connected with 'itsactuating shaft;

Figure 8 is a view essentially in-elevation, taken on the planes of thelines 8-8 in Figure 2;

Figure 9 :is a cross sectional view through Figure 8 on the plane of theline 9-9;

Figure 10 is 'a rear view of the control mechanism by which closure ofthe electric control circuit during one cycle of the machine manifestsits eifect during subsequent cycles of the machine;

Figure 11 is a detail sectional view through Figure 10 on the plane ofthe line 11-11;

Figure 12 is .a vertical sectional view through Figure l0 on the planeof the line 12-12;

Figure -13 is a back -view :of the control mechanism shown in Figure 10;

Figure 14 is a detail sectional view taken through Figure 13 on theplane of fl1e line 14-14; and

Figure 15 is 'a diagrammatic view of the entire control system withenough of the machine parts diagrammatically illustrated to show howdetection of a defective group of signatures during one cycle of themafchine locks out the stitcher heads during a subsequent cycle of themachine and effects the shifting of the routing control at the :deliverymechanism during a still later cycle of the machine.

Referring to the accompanying-drawings in which like numerals indicatelike parts throughout the several views, the numeral 5 designatesgenerally .a stitching machine of the type with which this invention ischiefly concerned. As is customary this machine is equipped with aninverted V-shaped saddle 6 upon which the groups of signatures S aresupported while being stitched, i. e. have wire staples driven throughtheir folds by stitcher heads 7 coacting with clincher boxes (not shown)located beneath the apex of the saddle in line with the stitcher heads.The number of stitcher heads used ordinarily depends upon the length ofthe book being stitched. In the machine illustrated two such stitcherheads are shown.

Though the manner in which the stitcher heads operate forms no part ofthis invention, it should be noted that in forming the stitches thestitcher head formers (not shown) are driven downward toward the saddle,and that this motion results from downward translation of :an operatingbar 8 with which driving lugs on the stitcher mechanism are connected;and that the stitcher heads are mounted on .a face plate 9 in a mannerallowing adjustment thereofxlengthwise of the saddle.

The operating bar 8 is raised and lowered by :an eccentric 10 in theback of the machine (not shown in Figure 1 but-diagrammaticallyillustrated in Figure 15.), the eccentric .being driven from its shaft:11 whenever a .clutch 12 is engaged. The engagement of this clutch 12is controlled by the calipering apparatus of this invention so that thestitcher heads :operate only when the group of signatures .in stitchingposition has passed the caliper without tripping it.

The shaft 11 revolves once each cycle of the machine and the clutch .12is of the pin type so that the determination of whether 'or not it shallbe engaged during any given cycle requires but a relatively briefportion of the cycle. In other words, if at the start of a cyclemechanism is actuated by which the clutch is held from engagement duringa few degrees of rotation of the shaft 11 the clutch cannot bethereafter engaged during that cycle even though the lock-out mechanismis no longer active.

The means by which the clutch 'is engaged is more or less conventionalto this 'art .and includes :a vertically reciprocable rod 13 (seeFigures 10 and 15) which is biased downwardly by a spring 14 'to effectengagement .of the clutch. Consequently by blocking the descent of therod 13 clutch engagement .can be prevented. To block the .descent :ofthe rod :13 when it .is desired to :lock :out the stitcher heads a latchlever 15 and a latch .finger 16 are provided. The lever 15 is mediallypivoted as at 17 upon the .adjacent portion 18 of the machine frame and.has :one end thereof connected ito the rod 13 as at 19. Itsother endcarries a latch keeper 20 'with which :the .latch finger .16 engageswhenever the stitcher heads .are to 'be locked out. As long .as thelatch finger 16 eis disengaged fromits keeper v20 the latch levlerlls isfree :to rock with the reciprocation :of the ro The manner in which theposition of :the latch finger 16 'is controlled will be hereinafterdescribed.

The groups of signatures to bestitched into books are deposited upon thesaddle 6 of the 'machine by a long conveyorchainZl which travels past aplurality of loading stations (not shown) where operators placeindividual pages :or signatures in position -to be picked up by pusher'pins '22 on the conveyor chain and by which thesuccessive pages orsignatures are gathered into complete groups .and the complete groupsare fed onto the saddle 6. A reciprocating cyclically operating grippermechanism (not shown) takes the .groups of signatures deposited on thesaddle 6 by the conveyor chain and advances them to a stitching positionproperly centered under the stitcher heads, and after .the stitchingoperation, moves the stitched books along "the saddle to -a ggliverymechanism indicated generally 'by the numeral Upon arrival at thedelivery mechanism .a cylically operating tucker blade (not shown) liftsthe stitched books off the saddle and .into the bite of delivery tapesby which ,good books .are deposited in a seriated row upon :a deliverytable 24. .Bad books, that is defective groups of signatures which havenot been stitched because they include either .too .few or .toomanysignatures, areautomatically:kept'from'heing delivered .onto the table24 and instead are .diverted into a reject path as .a result of theactuation of a routing director positioned above the apex of the saddleand so arranged that it normally directs the books forwardly onto thetable 24 but when shifted, it deflects them to the rear of the machine.

, The shifting of the routing director 25 is coordinated with thelock-out of the stitcher heads as will be hereinafter described, tobecome effective either during the cycle of the machine directlyfollowing that during which the stitcher heads were locked out or duringa later cycle, but in any event the shifting of the routing director toreject a defective group of signatures is timed to take place when it islifted by the tucker blade.

The shifting of the routing director like the lock-out of the stitcherheads is controlled by the calipering mechanism of this invention,indicated generally by the numeral 26, and'which, as shown in Figure 1,is positioned to act upon the groups of signatures before they aredeposited upon the saddle 6 of the machine and their advance is takenover by the reciprocating gripper mechanism (not shown).

Hence, the calipering mechanism operates upon the work during a cycle ofthe machine which at least directly precedes the cycle during which thatgroup of signatures is stitched and is at least two cycles ahead of theone during which that designated group of signatures (not stitched intoa book) arrives at the delivery mechanism. This entails the provision ofmechanism for delaying the manifestation of the calipering mechanismresponse to a defective group of signatures, upon the stitcher headlock-out mechanism and the routing director of the delivery mechanism.This time delaying mechanism, indicated generally by the numeral 27, islocated at the back of the machine adjacent to the latch lever 15 andgenerally consists of a plurality of control elements or buttons 28slidably mounted in a ratchet wheel or disc 29.

This ratchet wheel or disc is rotatably mounted on a bracket 30 solidlysupported from the frame of the machine, and is advanced stepwise by apawl 31. The pawl 31 is carried by a lever 32 oscillatable about theaxis of the ratchet disc and rocked by a cam 33 fixed to the shaft 11.The cam 33 positively advances the pawl and a tension spring 34connected to the lever 32 retracts the pawl.

To preclude damage to the mechanism in the event of an obstruction torotation of the ratchet disc 29, the link 35 through which the lever 32is connected with the follower of the cam 33 comprises twotelescopically connected sections normally held against separation by aheavy spring 36.

The control elements or buttons 23, as best shown in Figures 11 and 14,have uniform diameter shanks 37 slidably received in holes drilledthrough the disc 29, and enlarged heads 38 all overlying the rear faceof the disc 29. Snap rings 39 on the opposite ends of the stems preventdisassembly of the control elements or buttons from the ratchet disc.

As the ratchet disc 29 is rotated the control elements or buttons pass aresetting cam 40 positioned to have the heads 38 of the control elementscollide therewith, and as the heads 33 ride over the cam the controlelements, if depressed, are projected. In the projected positions of thecontrol elements, their heads 38 lie closely adjacent to the ratchetdisc to engage a follower roller 41 on the free end of a lever 42 fixedto a shaft 43 and positioned to swing across the disc in an are whichintersects the path of the heads of the control elements in normaldepressed position. The latch finger 16 is also secured to the shaft 43and a tension spring 44 having one end connected to the hub of the lever42 and its other end anchored as at 45 yieldingly rocks the shaft in aclockwise direction as viewed from the back of the machine (Figure 10)to swing the follower roller 41 into the path of the heads of thecontrol elements. Such clockwise rotation of the lever 42 about itsmounting is limited by the engagement of the latch finger 16 with itskeeper 20.

The mechanism is so timed that just before the rod 13 descends or is todescend to effect operation of the stitcher heads, the head of one ofthe control elements or buttons 28 collides with the roller 41 andswings the latch fingerlfi away from its keeper 20 to thereby allowrocking of the latch lever 15 and normal operation of the stitcherheads. The re-engagernent of the finger 16 with the keeper 20 is, ofcourse, automatic and takes place with the ascent of the rod 13coincidentally with the return of the stitcher head operating bar to itsraised position.

Since the pawl 31 is driven from the cyclically rotat ing shaft 11 itfollows that the ratchet disc advances one tooth with each cycle of themachine, and the control elements or buttons 28 are so spaced andpositioned that one of them is carried past the follower roller 41during each advance of the ratchet disc.

A depressed control element or button 28 does not collide with thefollower roller 41 but passes the same without contacting it. This isillustrated in dotted lines in the detail view, Figure 11. Consequently,to prevent the operation of the stitcher head or heads during a givenmachine cycle, it is necessary to depress the control element or buttonwhich moves past the follower roller 41 during that cycle.

The depression of the control elements or buttons 28 is eifected byrocking a bell crank lever 46 (Figure 12) about its pivotal support 47and thereby swinging its arm 48 toward the ratchet disc and against theprotruding end of the control element or button then under the arm 48. Atension spring 49 yieldingly holds the bell crank lever in its inactiveposition at which its arm 48 clears the protruding ends of the controlelements but this spring is overpowered by the energization of anelectromagnet 50, the armature of which is connected to the lever as at51. Energization of the solenoid 50 is under the control of the caliperas will be hereinafter described.

A depressed actuator element or button 28 not only allows the stitcherhead or heads to be locked out during a given cycle of the machine butalso effects shifting of the routing director 25 during the followingcycle or cycles. For this purpose a micro switch 52 is mounted injuxtaposition to the ratchet disc on an extension of the bracket 30 tohave its plunger 53 depressed by a medially pivoted actuating lever 54.(See Figures 12, 13 and 15.) The lever 54 is pivotally mounted on a stubshaft 55 anchored in the bracket extension with one end 56 of the leverdirectly over the plunger 53. The opposite end of the lever carries aroller 57 so positioned with respect to the ratchet disc as to lie inthe path of the head of any control element or button which has beendepressed. A tension spring 58 yieldingly holds the lever 54 in aposition at which its end 56 just clears the plunger 53, this positionbeing defined by a stop 59 with which a pad 60 on the lever collides.

Attention is directed to the fact that the rollers 41 and 57 are sopositioned with respect to one another that a depressed control elementor button 28 which has just passed the roller 41 without contacting itand thus leaving it and the latch finger 16 in the stitcher lock-outposition, collides with the roller 57 during the next cycle of machineoperation.

It should also be noted that the depressor or resetting cam 40 ispositioned to be traversed by any depressed control element or button 28before it moves under the arm 48 of the setting lever 46.

The arm 48 is wide enough to cover two control elements at once, acondition which is necessary with some types of work, but normally is ina position to depress only one of the elements. The arm 48 is secured tothe bell crank lever 46 by a screw 61 and a dowel pin 62 projecting fromthe lever and received in one of three holes 63 in the arm and arrangedin an arc about the axis of the screw. As best seen in Figure 10 whenthe arm 48 is in its position shown in full lines energization of thesolenoid 50 will depress one control element or button during the cyclejust preceding the cycle at which that control button moves opposite theroller 41. This affords a one cycle delay between the time the controlelement or button is depressed and the time its depressed conditioneflects lock-out of the stitcher head and two cycles before thatdepressed control element or button effects shifting of the routingdirector 25. This latter function is accomplished by the closure of themicro switch 5'2 which, as can be seen in Figure 15, closes a controlcircuit for a solenoid 64 by which the shifting of the routing directoris accomplished.

If on the other hand the arm 48 is secured to the bell crank lever 46 inits dotted line position shown in Figure 10 there will be a two cycledelay between the instant energization of the solenoid 50 effectsdepression of a control element or button and the time at which thatdepressed element or button moves opposite the roller 41; and if the arm48 is secured in :itsinterme'diate position, energization of thesolenoid 50 will cause the depression of two control elements or buttonsso that for two successive machine cycles the stitcher heads will belocked out and the routing director will be shifted to its positiondivertingthe delivered book or group of signatures to the reject path.

The routing director 25 of itself is not new in stitching machines ofthis kind, and as is customary, it comprises a plurality of endwisespaced aligned V-shaped elements all mounted upon a common rock shaft 66in "such a way that rocking movement of the'shaft swings the apex of the-shaped elements slightly forwardly or rearwardly with respect to theapex of the saddle 6, it being understood that the apexes of theV-shaped elements face and point toward the saddle.

The mechanism which controls the position and rocking of .the shaft 66,is diagrammatically illustrated in Figure 15 where it includes a latchbar 67 having a keeper recess 68 and a latch 69 normally engaged withthe keeper 68 but adapted to be lifted therefrom by energization of thesolenoid 64. A cyclically operating cam 70 and a cam follower 71 carriedby a lever 72 fixed on the shaft 66 provides means for cyclicallyrocking the shaft a slight distance in the direction to free the latch69 just before energization of the solenoid 64 would occur if a previousdetectionof a defective group of signatures required shifting therouting director.

The cam 70 also periodically rocks the shaft 66 to reengage the latch 69after the book has been delivered. Of course, as long as the latch 69remains in its latching position, that is as long as the solenoid 64 isnot energized, the slight rocking of the shaft '66 each cycle to freethe latch does not move the routing director from its norrraal positiondirecting the books onto the delivery table 2 The calipering mechanism'26 is mounted on a rigid pedestal 75 which straddles the bottom stretchof the conveyor chain 21 and is preferably positioned directly ahead ofthe receiving end of the saddle 6. A pair of upper and lower companionfeeler rolls 76 and 77, re spectively, constitute the work engagingelements of the caliper. The lower roll 77 is fixed to a shaft 78 havingits opposite ends journalled in bearings carried by a bracket 79 whichis firmly bolted to the top of the pedestal 75 in such a position thatthe roll 77 protrudes slightly through an opening 80 in the adjacentfront wing 81 of the saddle. The lower roll 77 is thus firmly mounted'to rotate about a fixed .axis parallel with the plane of the front wing81 of the saddle and so disposed with respectthereto that the peripheryof the roller protrudes slightly beyond the front face of this wing 81.

The roll 77 is driven from the conveyor chain 21 by means of a sprocketwheel 82 which meshes with the lower run of the conveyor chain 21, bevelgearing 83, a vertical shaft '84., spur gears 85 and bevel gears 86.

The upper roll 76 is also driven from "the conveyor chain to turn atexactly the same peripheral speed as the lower roll, by means of avertical shaft 87 whichextends up from the bevel gears 86 through thetop of the pedestal 75 and into a bracket 88 also bolted to the top ofthe pedestal 75.

It is important that the pedestal 75 and the brackets 79 and 88 boltedthereto be perfectly rigid so that any separation of the feeler rollsresulting from the passage of work 'therebetween will directly andreliably represent the thickness of the work. Hence, these parts must bemade strong enough to prevent deflection or spreading between the twobrackets.

The drive shaft "87 for the upper roll is drivingly connected throughbevel gears 89 with a jack shaft .90 journalled in top and bottom walls91 and 92, respectively, of a housing structure which forms the upperpart of the bracket '88. The shaft 90 protrudes above the top wall91 andhasa gear 93 keyed thereto. This gear meshes with a gear 94 which is.freely rotatably mounted on a stub shaft 95 carried by an arm 96arranged to swing about the axis of the shaft90.

The gear 94 has the upper roll 76 fixed thereon to turn in unisontherewith. Hence, though the arm 96 is free to swing about the shaft 90to thereby carry the upper roll 76 toward and from its companion roll77, the upper roll will be driven as well as the lower roll.

The arm 96 is preferably a casting with a :hub 97 in which the stubshaft '95 is secured,-and a hub 98 coaxial with the gear 93 and by whichthe lever is pivotally mounted to swing about the shaft 90. A covercasting 99 is secured to the top of the arm 96 'to provide a guard forthe "gears 93 and 94, and an offset portion of this cover provides anoutboard bearing for the stub shaft 95. A bored post 100 secured to thetop "wall 91 of the bracket 88 has the hub 98 of the arm freelyrotatably mounted thereon, and its bore provides a bearing for the hubof the gear 93 and consequently the upper end of the shaft 90. In thismanner the arm 96 is mounted to swing about the axis of the shaft 90.

A gear sector 101 is also mountedto swing about the shaft 90, themounting for the sector being'provided by its hub 1 02 embracing thehub-98 of the arm. Relative axial displacement between the gear sectorand pivoted arm 96 is prevented by having the hub 102 of the gear sectorconfined between a shoulder on the underside 'of the arm and a flange103 on the bored post 100. The flange 103 also provides a thrust bearingfor the arm 96.

Though the gear sector and arm are movable with respect to one another,during the functioning of the caliper they swing in unison about theaxis of the shaft 9%. To tie the gear sector and arm together for suchconjoint pivotal motion a heavy tension spring 104 connects the outerend of the gear sector with a pin 105 fixed in the outer end of the arm.The spring 104 draws the gear sector and arm together an amountdetermined by the settingof an adjusting screw 106.

The screw 106 is threaded in a block 107 mounted on the outer end of thegear sector and has its end bearing against a pad 108 on the outer endof a boss extended from the arm '96. A knurled head 109 providesmeansfor adjusting the screw, and a lock nut 110 serves to secure thescrew in adjusted position. As will be hereinafter more fully described,the adjustability of the relationship between the gear sector and arm 96provides means by which the caliper may be set to any prescribedthickness for the groups of signatures within the range of the machine.g

The arm '96 and consequently the upper feeler roll carried thereby isyieldingly urged toward the lower fee'ler roll by a spring 111 confinedbetween a spring seat 112 on the arm 96 and a spring stop 113 mounted onthe top wall '91 of the bracket '88. This spring tends to maintain thecompanion feeler rolls in engagement at all times but since it isdesirable to have the groups of signatures moved between the rollswithout opposition and also since it may 'be desirable to have thefeeler rolls contact the work for only part of its length, a controlearn 114 is provided by which the soca'lled down-time of the upperfeeler roll is determined. This control cam is mounted on a cam shaft115 parallel to the shaft 90 and journalled in the top and bottom walls91 and 9-2 of the bracket 88. Gears 1-16, 117 and 118 '(see Figure 8)drivingly connect the shafts 90 and 115.

The cam 114 (as best shown in Figure "6) comprises a top section 119and-a bottomsection 120 the latter having a hub by which it is securedto the upper end-of the shaft 115. The contour of the two cam sectionsis identical. Each has a concentric low and a concentric high and byinterfitt-ing cylindrical portions on the cam sections, they may berotated with respect to each other to increase or decrease the effectiveangular length of the high and low of the cam. Clamping screws 1-21provide means for securing the cam sections in any desired positionalrelationship.

As best shown in Figure 3 the earn 114 is tracked by a follower roller122 freely rotatably mounted on an'a'rm 1-23 which :is preferably formedas an integral part of the gear sector 101. The radii of the high andlow portions of the cam 114 are such that as long as the follower roller122 rides the high of the cam the upper feel'er roll is lifted clear ofits companion roll to allow work to pass freely between the rollswithout opposition and without having the rolls ride thereon. But whenthe low of the cam is opposite the follower 122 the cam has no effectupon the osition of the upper feeler roll;

Thus, the angular duration of the low of the cam determines thedown-time of the feeler roll, and in actual practice the :parts are soproportioned that with the cam sections 1 19 and 120 completely inregister so that the maximum low dwell is obtained the down-time is teninches of book travel, whereas when the cam sections are rotated withrespect to one another to reduce the low dwell of the cam to minimum, adown-time of five inches of book travel is allowed. In other words, byrotating the cam sections 119 and 1253 with respect to one another thedown-time of the feeler roll may be varied between a minimum of fiveinches and a maximum of ten inches of book travel.

Since the location of the length of the book or group of signaturestraversed by the caliper rolls is a function of the speed of the camshaft and since the spacing between the pusher pins on the conveyorchain which feed the groups of signatures to the stitching machine maybe at least either of two selected distances as, for instance tWenty-one(2l) inches and twenty-four (24) inches, it is necessary that means heprovided to coordinate the speed of the cam shaft with the length ofchain between the pusher pins. This latter distance is generallyreferred to in the art as chain travel.

The needed coordination between the speed of the cam shaft 115 and thechain travel is obtained by removing the gears 116 and 118 and replacingthem with gears of dif- 3 ferent diameter. This gear change alsoinvolves removing the idler gear 117 from its stub shaft 117 and transferring it to a stub shaft 125.

In addition to the cam 114, the cam shaft 115 also has a timing earn 126mounted thereon to close a micro switch 127 for a brief interval onceeach cycle of the machine. This cam 126 is secured to the underside of ahub on the gear 118 by means of clamping screws 128 in a manner allowingfor rotational adjustment of the cam about the cam shaft 115. By thisadjustment it is possible to select the location in the length of thework and the time during the machine cycle when the micro switch 127 isclosed.

The closure of the micro switch 127 is necessary to activate the controlcircuit 129 diagrammatically illustrated in Figure 15, but the closureof this switch of itself is not sufficient to do so. In addition one orthe other of two mercury switches 130 and 131 must be closed at the timethe micro switch 127 is closed. The closure of these mercury switchesresults from detection by the caliper of deviation from a prescribedthickness of the groups of signatures passing between the caliper rolls.Thus, if a group of signatures between the caliper rolls is thicker thanthe prescribed thickness or in other words the error is on the plusside, the switch 131 will be closed but if the error is on the negativeside, or in other words the group of signatures is thinner than theprescribed thickness, then the switch 130 Will be closed. In eitherevent, the control circuit 129 is completed during the interval themicro switch 127 is closed and as a result thereof the solenoid 50 isenergized to project one of the control elements 28 to its operativeposition.

The closure of the mercury switches 130 and 131 is the direct result ofbringing a permanent magnet 132 into proximity therewith. This magnet iscarried by a pendulum 133 swung in one direction or the other byrotation of a pinion shaft 134. The pinion shaft 134 is journalled inbushings mounted in bosses 136 and 137 projecting from the side of thebracket 88. At its upper end it has a pinion 138 fixed thereto whichmeshes with the gear sector 101 so that any swinging movement of thegear sector resulting from movement of the upper feeler roll toward orfrom its companion imparts rotation of the pinion shaft. To take upback-lash between the pinion and the gear sector a torsion spring 139encircles the pinion shaft and has one end anchored to the boss 136 andits other end secured to a collar 140 fixed on the shaft.

The lower end of the pinion shaft has an arm 141 secured thereon, as bya set screw or the like, to swing as the pinion shaft is turned. Beyondthe hub of the lever 141 the pinion shaft is reduced in diameter toprovide a shoulder 142 and against this shoulder there are clamped theinner races of two ball bearings 143 and 144, with a spacing washer 145interposed there between, the clamping being effected by a nut 146threaded on the outer end of the shaft. The outer race of the bearing143 has an intermediate lever 147 clamped thereto and the outer race ofthe bearing 144 has a lever 148 clamped thereto.

The outer end of the intermediate lever 147 has a pair of oppositelyprojecting stop lugs 149 and 150 projecting upwardly and downwardlytherefrom. These lugs coact with abutments 151 and 152 on the levers 141and 148, respectively. A tension spring 153 having one end anchored tothe lever 141 and its other end connected to the intermediate lever 147yieldingly holds the lugs 151 and 149 in engagement and a tension spring154 having one end anchored to the lever 148 and its other end connectedto the lever 147 holds the lugs 150 and 152 in engagement.

Consequently, if swinging movement of the pendulum 3 is not interferedwith or arrested the pendulum swings in unison with the arm 141 which isfixed to the pinion shaft 134 but if free swinging movement of thependulum is prevented or the extent of its movement is restricted, thenthe tension springs 153 and 154 permit overtravel of the pinion shaft134 in either direction. Since the ratio of the gear sector and pinionand the length of the pendulum greatly multiply any bodily movement ofthe upper feeler roll (the actual amplification of motion being in theneighborhood of one to forty), such overtravel is necessary to enableadjustment of the mechanism to different thicknesses of stock and toprevent damage to the parts by substantial movement of the upper feelerroll away from its companion as, for instance, each time the cam 114lifts the feeler roll. This relatively great multiplication of motionmakes the caliper extremely sensitive. A difference of as little asthree-thousandths of an inch (.003) can be reliably detected since sucha movement at the upper feeler roll produces a movement of one hundredtwenty thousandths of an inch (.120) at the end of the pendulum if it isnot restrained. This distance between mercury switch 130131 and themagnet 132 is sufficient to prevent closure of the switches.

If the caliper is set to trip at plus or minus threethousandths of aninch (.003"), which represents very thin stock, the travel of thependulum in either direction from its neutral position is limited to theamount it is swung by such .003" deviation of the upper roll from itsprescribed position, and to limit the travel of the pendulum a boss 155thereon collides with one or the other of two adjustable stops 156 and157. These stops are threaded into brackets 158 and 159 slidably mountedupon a base plate 160. The mercury switches are also carried by thesebrackets, the switch 130 being mounted on bracket 15S and the switch 131on bracket 159.

To slide the brackets along the base plate 160 and thereby enableadjustment of the switches toward and from the pendulum, each brackethas a screw 161 projecting therefrom and slidably passed through alignedholes in a pair of arms 162 projecting forwardly from and fixed to thebase plate, with a nut 163 threaded on the screw and confined betweenthe arms 162. Lock nuts 164 also threaded on the screws 161 secure thebrackets in adjusted positions.

In setting up the mechanism for a given job a group of signatures of thecorrect thickness is placed between the companion feeler rolls. Thiswill undoubtedly cause the pendulum to be swung toward the right (Figure8) the full distance allowed by the setting of the stop 157, theovertravel of the pinion shaft being accommodated by the spring 154.With a proper group of signatures thus positioned between the feelerrolls the screw 109 is turned to adjust the angle between the lever 96and the gear sector 191 until the rotation of the pinion shaft 134resulting from such adjustment brings the pendulum to its neutralvertical position. At this adjustment the lock nut 110 is tightened.

The thickness of the group of signatures between the feeler rolls isnext diminished by the thickness of one signature which, forillustration, may be three-thousandths of an inch (.003) and, of course,is accomplished by simply removing one of the signatures. Suchdiminution of the thickness of the group of signatures between thecaliper rolls results in rotation of the cam shaft 134 in a clockwisedirection as viewed in Figure 8 and a consequent movement of thependulum to the left toward the mercury switch 138. It should, ofcourse, be understood that the brackets 158 and 159 should be apart farenough during this setting operation to preclude interference with freeswinging movement of the pendulum.

With the pendulum swung toward the left, as viewed in Figure 8, theamount caused by the one sheet reduction in the thickness of the groupof signatures between the calipering rolls, the bracket 158 is carefullyadjusted toward the pendulum until its mercury switch 130 is closeenough to the magnet 132 to be closed by the attraction of its mercurytoward the magnet. Then 1.1 with the bracket 158 locked in this positionthe stop 156 is adjusted to bring the same just up against the lug 155.This completes the adjustment for the detection of a negative deviationfrom the prescribed thickness of the work.

To set the mechanism for the detection of a positive deviation fromprescribed thickness, the group of signatures between the caliperingrolls is increased in thickness by the addition of one more than theproper number, whereupon the pinion shaft 134 is rocked in acounterclockwise direction, as viewed in Figure 8, to swing the pendulumto the right and toward the mercury switch 131. The same adjustment asdescribed in connection with the switch 130 is then made for the switch131, that is, its bracket 159 is adjusted along the base plate to bringthe switch into the zone of influence of the magnet and then the stop157 is adjusted to bring the same just up against the lug 155.

With these adjustments made, any movement of the upper feeler rollresulting from deviation in the thickness of the work passingtherebetwcen either on the positive or the negative side by an amountequivalent to the thickness of one signature will cause one or the otherof the switches 130-131 to be closed. Movement of the upper feeler rollin excess of that amount, though producing an overtravel of the pinionshaft 134, will have no effect upon the mechanism due to the fact thatthe motion of the shaft 134 is transmitted to the pendulum only throughthe springs 153-154.

To assure against false detection which might result from the adherenceof a piece of paper or other substance on the surface of the feelerrolls, each feeler roll is equipped with a wiper 165 which is springbiased against the periphery of the rollers and to guide the groups ofsignatures smoothly between the feeler rolls a shoe 166 is mounted inthe path of the groups of signatures approaching flne feeler rolls toflatten and hold them against the wing 81 of the saddle.

From the foregoing description taken in connection with the accompanyingdrawings, it will be readily apparent to those skilled in this art thatthis invention provides an absolutely reliable and extremely sensitivecalipering mechanism especially adapted to signature stitching machinesto prevent the operation of the stitcher heads upon the presentment tothe machine of defective groups of signatures and to prevent thedelivery of such defective groups of signatures along with the goodstitched books. It will also be apparent to those versed in this artthat this invention aifords the same reliable and sensitive control inwork requiring two cycles of the machine operation to effect stitchingof the book as well as work which can be stitched in one cycle. Otheradvantages of the invention lie in the fact that while its use of anelectric control circuit affords instantaneous manifestation of thedetection of imperfect work, its novel control unit can delay the effectof this manifestation until subsequent cycles of a machine equipped withthis invention; and. that while the invention is especially valuable ona signature stitching machine it is readily adaptable to other machineshandling sheet material.

What we claim as our invention is:

1. In a cyclically operating machine of the character described havinginstrumentalities which perform an operation upon the work passingthrough the machine, the combination of means for preventing theoperation of said instrumentalities upon the presentation of defectivework, comprising: an electric control circuit; trip means controlled bysaid circuit and operable upon actuation to prevent the operation ofsaid instrumentalities; a. pair of switches connected in series in saidcircuit, both of said switches being biased to positions maintaining thecircuit inoperative to actuate the trip means; cyclically operatingmeans driven by the machine and connected with one of said switches toactuate the same against the bias thereon once each cycle of the machineto a position at which it would render the circuit operative to actuatethe trip means providing the other switch were also in a position torender the circuit operative; detector means positioned to operate uponthe work being fed to said instrumentalities, said detector means beingsensitive to a predetermined defectiveness in the work and operable uponits detection to produce a response capable of actuating an electricswitch; and means connecting the detector means with said other switchto translate a switch actuating response at the detector means intoactuation of said other switch against the bias thereon to its positionnecessary to render the circuit operative to actuate the trip means.

2. The structure set forth in claim 1 further characterized by theincorporation in said trip means of means for delaying itsmanifestation, comprising a plurality of control elements constrained tomovement in unison along a defined recurrent path; machine driven meansfor indexing said control elements along said path; said controlelements being shiftable between operative and inoperative positions onsaid path; electrically responsive means connected in the controlcircuit and operable upon actuation thereof to shift one of the controlelements to its operative position; and mechanism positioned to beactuated by a control element in operative position upon engagement ofsuch element therewith.

In a signature stitching machine including a saddle along whichsignatures to be stitched into books are advanced, and a stitcher headfor stitching said groups of signatures into books, the combination ofmechanism for preventing the operation of the stitcher head upon thepresentation thereto of a group of signatures which is defective due toits being either too thick or too thin, comprising: lock-out mechanismfor restraining the operation of the stitcher head; an electricallyresponsive trip device for actuating said lock-out mechanism; a controlcircuit for said electrically responsive trip device; a pair of electricswitches connected in series in said control circuit; means providing areference surface over which the groups of signatures move in theirpassage to the stitcher head; a feeler roll; means mounting the feelerroll opposite the reference surface and for movement thereof toward andfrom the same so that the groups of signatures pass between the feelerroll and said surface and the positional relationship between the feelerroll and the reference surface depends upon the thickness of the groupsof signatures passing therebetween; means biasing the feeler roll towardsaid reference surface; a connection between one of said two switchesand said feeler roll whereby movement of the feeler roll from apredetermined positional relationship with respect to the referencesurface in consequence to the passage of a defective group of signaturestherebetween closes said switch and holds the same closed as long assaid roll and the defective group of signatures are in engagement; andmachine driven means connected with the other switch and operable toclose the same for an interval of the time the feeler roll is inengagement with each succeeding group of signatures.

4. In a cyclically operating machine having instrumentalities operableupon work presented thereto, and having cyclically operating means forpresenting work to said instrumentalities, the combination of means forpreventing the operation of said instrumentalities upon the presentationthereto of work which deviates from a prescribed normal condition, saidmeans comprising a plurality of spaced apart movable control elements;means timed with the cyclic operation of the machine for advancing saidcontrol elements along a predetermined recurrentpath, said controlelements being movable to and from an operative position; meanspositioned in the path of the control elements and actuatable by acontrol element in operative position to prevent the operation of saidinstrumentalities; electrically responsive means positioned adjacent tothe recurrent path of the control elements ahead of the point in saidpath at which an operative control element actuates the means forcontrolling said instrumentalities, said electrically responsive meansbeing operable to move a control element to its operative position;detector means positioned to act upon work being moved toward saidinstrumentalities; and a control circuit for said electricallyresponsive means connected between it and said detector means andgoverned by the detector means, said detector means activating thecontrol circuit by its response to deviation from a predeterminedcondition of the work passing the detector means.

5. In a signature stitching machine having a cyclically operatedstitcher head, a delivery mechanism including means for routing thefinished work one way or the other, and cyclically operating mechanismfor advancing groups of signatures to the stitcher head and from thestitcher head to the delivery mechanism, the com bination of: mechanismfor locking out the operation of the stitcher head; mechanism forshifting said routing device; a calipering device positioned to act ongroups of signatures moving toward the stitcher head; electrical- 1yresponsive means for rendering said stitcher head lockout mechanismeffective and for shifting said routing device; a control circuitgoverned by said calipering device for activating said electricallyresponsive device; and time delay means for delaying the response of thestitcher head lock-out mechanism and the routing device of the deliverymechanism to take place during cycles of the machine subsequent to thatin which detection of a bad group of signatures is made.

6. In a signature stitching machine having a stitcher head normallyoperated during each cycle of the machine, the combination of means forpreventing the operation of the stitcher head upon the presentationthereto of a group of signatures which fails to have a predeterminedthickness, comprising: an electric control circuit; trip meanscontrolled by said circuit and operable upon actuation to prevent theoperation of said sticher head; a pair of switches connected in seriesin said control circuit, both of said switches being biased to positionsmaintaining the circuit inoperative to actuate the trip means;cyclically operating means driven by the machine and connected with oneof said switches to actuate the same against the bias thereon once eachcycle of the machine to a position at which it would render the circuitoperative to actuate the trip means providing the other switch were alsoin a position to render the circuit operative; a mechanical caliperpositioned to operate upon the groups of signatures being fed to thestitcher head, said caliper including a feeler movable from apredetermined position in consequence to deviation from a prescribedthickness of the groups of signatures passing the caliper; and meansconnecting the caliper with said other switch to translate movement ofthe feeler into actuation of said other switch against the bias thereonto its position necessary to render the circuit operative to actuate thetrip means.

7. In a signature stitching machine, having a normally cyclicallyoperated stitcher head, a delivery mechanism including a routing devicefor directing the work leaving the machine one way or another, andcyclically operating mechanism for advancing groups of signatures to thestitcher head and from the stitcher head to the delivery mechanism, thecombination of: a caliper positioned to inspect the groups of signaturesmoving toward the stitcher head and having a feeler movable from anormal position in response to the detection of a group of signatureswhich fails to have the prescribed thickness; mechanism for preventingthe operation of the stitcher head and for effecting the shifting of theelectrically responsive means for activating said last named mechanism;a control circuit for said electrically responsive means including apair of switches connected in series, so that both of said switches mustbe closed to effect the functioning of said electrically responsivemeans; means connecting one of said switches with the movable feeler andthrough which movement of the feeler in either direction in consequenceto deviation in thickness of the group of signatures passing through thecaliper, effects closure of said switch and retains it closed for aslong as the deviation in thickness is detected by the caliper;cyclically operating means for closing the other switch once during eachcycle of the machine; and means for delaying the effect of the operationof said electrically responsive means which results from concurrentclosure of said two switches to a cycle subsequent to that during whichsuch concurrent closure of the two switches took place.

8. The combination set forth in claim 7 further characterized by thefact that the means for delaying the effect of the operation of saidelectrically responsive means comprises a plurality of movable controlelements; means mounting and constraining the control elements tomovement along a recurrent path while enabling shifting thereof fromnormal inoperative positions to operative positions; machine drivenmeans for indexing the control elements a step at a time along theirrecurrent path; means actuated by the electrically responsive means andlocated at one point in the path of the control elements for shifting acontrol element to its operative position; means cooperable with acontrol element in operative position to activate the means forpreventing operation of the stitcher head; and other means cooperablewith a control element in operat ve position for activating the meansfor effecting the shiftrouting device;

ing of the routing device, said two means which cooperate with a controlelement in operative position being located at spaced points in the pathof the control elements beyond the point at which the control elementsare shifted to operative position and so positioned as to be reached bythe control element in operative position during machine cyclessubsequent to that at which the control element was shifted to operativeposition.

9. In a cyclically operating machine which performs work upon sheetmaterial fed thereto and has instrumentalities to perform one operationduring one cycle of the machine and other instrumentalities to performanother operation upon the sheet material during a subsequent cycle ofthe machine, the combination of means for preventing the operation ofsaid instrumentalities if the sheet material fed thereto is imperfect,said means comprising: a detector positioned in the path of the sheetmaterial being fed through the machine and responsive to detection of animperfect condition of the sheet material; an electric switch closed bysuch response of the detector; another electric switch; means driven bythe machine for closing said other switch once each cycle of themachine; a control circuit having said two switches connected in seriestherein so that concurrent closure of both is required to close thecontrol circuit; mechanism for controlling each of saidinstrumentalities; electrically responsive means connected in saidcontrol circuit for actuating said mechanisms; and means for delayingthe effect upon said mechanisms of the activation of the electricallyresponsive means until the sheet material which occasioned the responseof the detector arrives at each of said instrumentalities.

10. A caliper for sheet handling machines, comprising: coacting feelermembers between which the sheet material passes; means mounting one ofsaid feeler members for pivotal movement toward and away from the otherfeeler member; means for operating the movable feeler member atpredetermined intervals; a pair of spaced apart mercury switches; apendulum having its free end portion disposed between said switches;means mounting said pendulum for pivotal movement about an axisindependently of the pivotal axis of the movable feeler member; apermanent magnet carried by the free end portion of the pendulum. andoperable upon movement thereof into proximity with either of saidswitches to effect closure thereof; and a motion transmitting connectionbetween the pendulum and the movable feeler member through whichmovement of the latter toward the other feeler member an extent inexcess of a prescribed distance positions the pendulum to effect closureof one of said switches, and movement of the movable feeler membertoward the other feeler member an extent less than said prescribeddistance positions the pendulum to effect closure of the other of saidswitches.

11. A caliper for sheet handling machines, comprising: a rigid referencesurface across which the sheet material passes; a movable feeler memberopposite said reference surface; means urging said movable feeler membertoward the reference surface, said movable feeler member occupying apredetermined position as long as the sheet material moving between itand the reference surface does not deviate from a prescribed thickness;a pivoted arm connected with the movable feeler member to be swung bymovement of said feeler member in either direction from itspredetermined position; a pendulum mounted to swing about a fixed axisspaced from the axis about which the arm swings; a motion transmittingconnection between the pendulum and said arm including a gear on the armmeshing with a pinion concentric to the axis about which the pendulumswings; and means located adjacent to the free end of the pendulum fortranslating swinging movement of the pendulum in either direction from anormal vertical position into a control impulse.

12. The caliper set forth in claim 11 further characterized by theprovision of: stop means for limiting swinging movement of the pendulum;and yieldable means in the motion transmitting connection locatedbetween the pinion and the pendulum so that rotation of the pinion maybe continued despite stoppage of swinging movement of the pendulum.

13. A caliper for sheet handling machines, comprising: a movable feelerroll; a pivoted lever mounting said feeler roll in position forengagement with the sheet material passing through the machine, saidlever holding the feeler roll i112 engagement with. the sheet materialand enabling movement of the roll in one direction or the other withdeviation. from a prescribed thickness of the sheet material; a. gearsector pivoted to swing about the axis of the arm which carries themovable feeler roll; a pinion mounted to rotate about a fixed axismeshing with the gear sector; a. lever mounted to swing about the axisof the pinion; stop means limiting the swinging movement ofthe lever toa predetermined are extending to opposite sides of a neutral position; ayieldable motion transmitting connection between the pinion and saidlever through which. the lever is held in its neutral position when thefeeler is in contact with sheet material of the prescribed thickness,and through which rotation of the pinion in consequence. to motion ofthe feeler roll normally effects swinging movement of the lever, theyieldability in the motion transmitting connection enabling rotation ofthe pinion due to abnormal movement of the feeler roll even though theswinging movement of the lever has been stopped; an adjustableconnection between the gear secfor and the arm carrying the movablefeeler roll and through which the relationship between the feeler rolland. the lever may be varied to enable the lever to assume its neutralposition with any prescribed thicknesses of the sheet material; andmechanism in juxtaposition to the free end portion of the lever fortranslating movement thereof in either direction from its neutralposition into a control impulse.

14. In a calipering device of the character described: a pair of spacedapart mercury switches; a pivoted lever mounted with a free end portionbetween said switches; a permanent magnet carried by said free endportion of the lever, the spacing between the switches being such thatwith the lever in a position substantially equispaced from the twoswitches the permanent magnet carried thereby has no effect upon theswitches; a movable feeler mounted independently of said lever to movefrom a position spaced clear of the material to be calipered toward andinto engagement with said material; means for operating said feeler; anda driving connection between said feeler and said lever through whichmovement of said feeler an extent in excess of a prescribed distance toengage said material positions said lever to bring said magnet intoswitch closing proximity with one of said switches, and movement of saidfeeler an extent less than said prescribed distance'positions saidfeeler to bring said magnet into switch closing proximity with the otherof said switches.v

15. In a caliperi ng' device of the character described, the structureset forth in claim 14 but wherein the pivoted lever is a pendulumnormally hanging in a vertical position.

16; In a calipering device of the character described, the structure setforth in claim 14 further characterized by the provision of stop meansfor limiting the swinging movement or" the pivoted lever in eitherdirection to preclude collision" thereof with the mercury switches; andfurther by the incorporation of yieldable means in the drivingconnection between the movable feeler and the pivoted lever throughwhich overtravel' of the feeler with respect to the permitted motion ofthe leveris accommodated.

17. In a caiipering device of the character described: amovablefeelermember movable in either direction from a position corresponding to thecorrect thickness of the material being calipered; an arm mounted toswing about a fixed axis; a motion transmitting connection between themovable feeler member and said arm through which movement of the feelermember swings the arm about its mounting, said motion transmittingconnection multiplying the motion of the feeler member so that arelat-ively small motion on the part of the feeler member swings thefree end of the arm through a substantial arc; a pair of mercuryswitches each adapted to be closed by bringing a magnet in closeproximity thereto; a permanent magnet carried by the free end portion ofthe arm; and means mounting said mercury switches at opposite sides of'the free end portion of the arm and across the path of the permanentmagnet carried thereby but spaced apart a distance sufficient to preventclosure of the switches by the permanent magnet as long as the arm is ina neutral position corresponding to the position of the feeler memberwhen the material being calipered has the correct' thickness.

L8. In a caliper of the character described, the struc- 16 tures setforth in claim 17 further characterized by the provision of: means foradjusting the mercuryswitches toward and from one another to therebyenable greater or lesser swinging movement of the pivoted arm; stopsfixed with respect to the mercury switches and cooperable with a part onthe pivoted arm topositively limit the swinging movement thereof; andyieldable means forming part of the driving connection between thepivoted arm and the movable feeler member for accommodating travel ofthe feeler member beyond points corresponding to the limitations ofswinging movement of the pivoted arm.

19. In a signature stitching machine having a conveyor chain foradvancing groups of signatures to be stitched, the combination of meansfor calipering the group's'of'signatures and closing an electriccircuit- .upon' detection of deviation from a prescribed thickness forthe. groups of signatures being advanced by the conveyor chain, saidmeans comprising: a timing. switch; a rotatablecarn for periodicallyclosing the timing switch; a drive for said cam driven by the conveyorchain, said drive timing the rotation of the cam to effect closure ofthe timing switch once for each fixed amount of chain travel;complementary feeler rolls mounted to have the groups ofsignatures passtherebetween; means mounting one of the rolls for movement thereoftoward and from the other;.means biasing said movable roll toward theother; a rotatable cam reacting against said biasing means. andcontrolling the periods of cooperation between said rolls; means drivenby the conveyor chain for rotating said last named cam so that theperiods of cooperative relationship between the rolls is coordinatedwith the closure of the timing switch; a pair of switches connected inseries circuit with'the timingv switch; and switch closing meansconnected with the movable roll for closing one or the other of saidpair of switches in response to movement of the movable roll in eitherdirection from a predetermined positional relationship with respect tothe other roll.

20. In a calipering device of the character described; a pair ofcompanion feeler rolls; a pivoted arm mounting one of the feeler rollsfor movement toward and from the other; an electrical control circuit; amember arranged to be electrically actuated by said circuit; a normallyopen electric switch connected in said circuit; a switch closingmechanism drivingly connected with said pivoted arm and operable toclose the switch upon movement ofthe arm occasioned by movement of themovable roll from a predetermined positional relationship with respectto its companion; a normally open electric timing switch connected insaid circuit, both said switches when closed rendering said circuitoperative to electrically actuate said member", a cam shaft; a pair ofcams on said shaft; a cam follower riding on one of said cams andconnected with the timing switch for periodically closing the same asthe cam shaft rotates; and a cam follower connected with said pivotedarm and riding on the other cam tolift' the movable roll out ofcooperative relationship with its companion during partof the rotationof the cam shaft, whereby said cam shaft coordinates the closure of thetiming switch with the periods of cooperation between the rolls.

21. In a calipering device of the character described: a movable feelerrolli adapted to ride the work to be calipered; a pivoted supporting armcarrying said movabie feeler roll for' downward movement toward the workand upward movement therefrom; a spring acting on said pivoted arm. andyieldingly biasing the same downward to hold the roll in engagement withthe work being calipered; a rotatable cam for controlling the down timeof the roll; a cam follower connected with the pivoted arm and riding onsaid cam to lift the roll out of operative engagement with the workduring part of the rotation of the cam while allowing the roll tooperatively engage the work during the remainder of the rotation of thecam; an electrical control circuit; a member arranged to be electricallyactuated by said circuit; a normally open electric switch connected insaid circuit; switch actuating mechanism connected with the pivoted armand operative to close the switch in response to movement of the armcaused by response of the feeler roll to deviation from a prescribedcondition of the work; an electric timing switch connected in saidcircuit in series with said first namedswitch, both said switches whenclosed renderlng said circuit operative to electrically actuate saidmember; a-camfor closing said timing switch; and a common cam shaft forsaid two cams, said cams being rotationally adjustable with respect toone another about the cam shaft so that the period of closure of thetiming cam may be adjusted to take place during a predetermined part ofthe down time of the feeler roll.

22. In a stitching machine having a saddle upon which groups ofsignatures are supported during the stitchlng operation, and a conveyorchain for advancing groups of signatures to the saddle, the combinationof calipering device for calipering the groups of signatures beingadvanced to the saddle and for preventing the operation of certaininstrumentalities of the machine upon the passage of a group ofsignatures which fails to have a prescribed thickness, said caliperingdevice comprising: a pair of companion upper and lower feeler rollsmounted in the path of the groups of signatures advanced by the conveyorchain with their peripheries engageable upon a plane substantiallytangent to the outer face of one wing of the saddle; the lower rollbeing rotatable about a fixed axis; a pivoted arm carrying the upperroll for bodily up and down movement from and toward the lower roll; aspring acting upon said pivoted arm and yieldingly urging the same inthe direction to hold the upper roll down on the lower roll and thus ontop of the groups of signatures passing between the rolls; a camreacting against said spring to lift the upper roll away from itscompanion and to hold the same out of coaction therewith for part of themovement of the upper roll toward and from its companion during theremainder of the rotation of the cam; an electric switch; switchactuating mechanism drivingly connected with the pivoted arm andoperable to close said switch upon movement of the arm with the movablefeeler roll out of a predetermined normal position corr sponding to aprescribed thickness for the groups of sinnatures: a timing switchconnected in series circuit with the first named switch so that bothswitches must be closed to effect the desired control function; a timingcam operable to periodically close the timing switch; a common cam shaftfor said two cams; and means driven from the conveyor chain for rotatingthe cam shaft so that the period of possible concurrent closure of thetwo switches is coordinated with the advance of the groups of signaturesby the conveyor chain.

23. A calipering device of the character described, comprising: a pairof companion stationary and movable feeler rolls; means mounting thestationary roll for rotation about a fixed axis; means mounting themovable roll for rotation about an axis parallel to that of thestationary roll and for bodily movement toward and from the same; commondrive means for rotating both rolls in unison and with identicalperipheral speeds; means biasing the movable roll toward the stationaryroll; a cam reacting against said biasing means for controlling theperiods during which the rolls are in cooperative relation capable ofeffecting a calipering function; an electric switch; switch closingmechanism connected with the means for mounting the movable roll andoperable to close the switch whenever the movable roll deviates from apredetermined positional relationship with respect to the stationaryroll; a timing switch connected in series circuit with said first namedswitch so that both switches must be simultaneously closed to effecttheir controlling function; a timing cam for periodically closing thetiming switch; a common cam shaft for the two cams so that the relativepositions of the cams on said common cam shaft determines whensimultaneous closure of both switches can take place; and means fordriving the cam shaft from the drive of the feeler rolls.

24. In a calipering apparatus of the character described: a movablefeeler engageable with the work to be calipered and movable one way orthe other in response to deviation from a prescribed thickness of thework; a pair of electric switches to be closed by such movement of thefeeler; a gear sector pivoted to swing about a fixed axls and connectedwith the movable feeler to be swung by movement of the feeler from apredetermined normal position; a pinion meshing with the gear sector; apinion rotation of said cam while allowing free.

18 shaft on which the pinion is secured; and switch closing mechanismconnected with the pinion shaft and operable by rotation of the pinionshaft in one direction to close one of said switches and upon rotationin the opposite direction to close the other switch.

25. In a calipering apparatus of the character described: a movablefeeler; a pivoted arm carrying said feeler for movement toward and fromthe work being calipered; means biasing said arm in a direction to holdthe feeler against the work being calipered so that deviation from aprescribed thickness of the Work effects swinging movement of the arm inone direction or the other; a gear sector connected with the arm to berocked by movement of the arm; a pinion meshing with the gear sector; apinion shaft on which the pinion is fixed; a pendulum mounted to swingabout the axis of the pinion shaft; instrumentalities mounted adjacentto the free end of the pendulum to be actuated by swinging movement ofthe pendulum in either direction from a neutral position; and a drivingconnection between the pinion shaft and the pendulum through whichrotation of the pinion shaft effects swinging movement of the pendulum.

26. The calipering apparatus of claim 25 further characterized by thefact that said driving connection between the pinion shaft and thependulum comprises a lever fixed to the pinion shaft; a lever fixed tothe pendulum but free with respect to the pinion shaft; an intermediatelever free with respect to the pinion shaft and the pendulum, all ofsaid levers being pivotal about the axis of the pinion shaft;cooperating stop abutments on said levers; and springs holding said stopabutments in engagement so that all of said levers and the pendulum movein unison with rotation of the pinion shaft unless movement of thependulum is interfered with.

27. In a signature stitching machine having a normally cyclicallyoperated stitcher head and cyclically operating means for advancinggroups of signatures to the stitcher head, the combination of: mechanismfor preventing the operation of the stitcher head; and means fordetecting during one cycle of the machine a group of signatures whichfails to meet prescribed thickness and for actuating the mechanism forpreventing operation of the stitcher head during a subsequent cycle ofthe machine, said means comprising a caliper positioned to caliper thegroups of signatures being advanced to the stitcher head, a plurality ofmovable control elements, means mounting and constraining the controlelements to movement along a recurrent path while enabling shiftingthereof from normal lnoperative positions to operative positions,machine driven means for indexing the control elements along theirrecurrent path once during each cycle of the machine, means actuated byresponse of the caliper to detectlon of a group of signatures whichfails to have the prescribed thickness, and located at one point in thepath of the control element for shifting a control element to itsoperative position, and means located to coact with a control element inoperative position to render operative the means for preventingoperation of the stitcher head, said last named means being positionedto be reached by a control element in operative position during a cycleof the machine subsequent to that during which said element was shiftedto its operative position.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,077,818 Eager Nov. 4, 1913 1,172,294 Krum Feb. 22, 19161,236,181 Kast Aug. 7, 1917 1,644,192 Kast Oct. 4, 1927 2,166,709Swanson July 18, 1939 2,179,517 Pelosi Nov. 14, 1939 2,264,067 ChambersNov. 25, 1941 2,473,683 Hines June 21, 1949 2,530,003 Crowley Nov. 14,1950 2,533,310 Carrette Dec. 12, 1950 2,538,536 Ritchie et al. Jan. 16,1951 2,556,895 Baker June 12, 1951 2,578,276 Yarnall et a1. Dec. 11,1951

